The present invention relates to a yarn consisting of at least one textile thread containing metallic fibers and other fibers, for example man-made fibers, the majority of the metallic fibers or the total content of metallic fibers being arranged within the inner cross-sectional area (2) of the textile thread (1), while the outer cross-sectional area (3) of the textile thread (1) sheathing the inner cross-sectional area (2) consists predominantly or exclusively of fibers well tolerated by the skin, particularly natural fibers and/or man-made fibers. Furthermore, the invention relates to the production and use of said yarn.
A yarn was proposed for the production of a fabric used for shielding electromagnetic radiation, which consists of steel fibers, polyester fibers and polyamide fibers spun into a textile thread which either forms the yarn itself or several of which textile threads are twisted into a yarn. On the average the steel fibers, polyester fibers and polyamide fibers of this textile thread are distributed uniformly over the cross-section of the textile thread.
A fabric consisting of such textile threads has a number of disadvantages:
(a) Since a very considerable portion of the steel fibers is externally exposed and thus contacts the skin of a person wearing for example a shirt made of such a fabric without a garment underneath, such a fabric is tolerated only poorly by the skin because the steel fibers do not only scratch the skin but also effect for example itching, allergies, etc. PA1 (b) Although the above-mentioned drawback resulting from the fact that the fabric contacts the skin of the user can be eliminated by underlining the garment made of this fabric, this results in poor wearing qualities apart from the costs and material needed for the underlining since the garment becomes too warm due to this underlining. PA1 (c) Externally, i.e. on the side facing away from the wearer's skin, the exposed steel fibers are also disadvantageous, particularly insofar as it is unpleasant to externally touch a garment made of this fabric and the steel fibers are disadvantageous for garments worn thereover since they effect heavy wear and tear on such garments, etc. PA1 (d) Another drawback consists in that the steel fibers impart a slightly gray appearance to the fabric, which can be changed by dyeing the fabric where this slightly gray appearance is not desired. However, such a dyeing does not always lead to beautiful colors, and the color the fabric obtains through dyeing cannot be determined in advance with sufficient accuracy since the steel fibers do not take the dye and as a result cause a gray tinge. Due to the gray tinge of the steel fibers light colors therefore become "dirty". PA1 (e) Although the last two drawbacks referring to the external effect of the fabric can be overcome by covering the fabric with a fabric free of steel fibers or the like, this deteriorates the wearing qualities even more since the user of such a garment feels even warmer than already is the case with the above-mentioned underlining in any case, the material required and the costs increasing even more as a result of lining. PA1 (a) to optimize the relation between shielding capacity of the yarn and weight proportion of metallic fibers and PA1 (b) to impart to the inner cross-sectional area of the textile thread certain desired textile properties obtainable by non-metallic fibers such as sweat-soaking or absorbing properties. PA1 (1) The structure of the yarn according to this invention may be such that the inner cross-sectional area of the textile thread consists of a fiber bundle or strand not processed into yarn or twisted yarn as such, which is made of metallic fibers alone or of metallic fibers to which other fibers, particularly man-made fibers and/or natural fibers, are added and that the fibers well tolerated by the skin, particularly natural fibers and/or man-made fibers well tolerated by the skin, which sheath the fiber bundle or fiber strand are processed into a yarn along with the fiber bundle or strand. PA1 (2) The structure of the yarn according to this invention may also be such that the inner c.degree. ross-sectional area of the textile thread consists of a yarn or twisted yarn made of metallic fibers alone or of metallic fibers to which other fibers, particularly man-made fibers and/or natural fibers, are added. This inner cross-sectional area is sheathed by fibers well tolerated by the skin, particularly natural and/or man-made fibers well tolerated by the skin, which are spun with the yarn forming the inner cross-sectional area into the textile thread.
EP-A-250 260, GB-A-2 018 323 and FR-A-2 599 762 disclose yarns containing metal only within the inner cross-sectional area, while the outer cross-sectional area is made of textile material. However, the metal is provided as a metal wire or several parallel metal wires within the yarn. Such metal wires have a number of drawbacks. One of these drawbacks consists in that the yarn becomes relatively stiff, and it becomes the stiffer, the thicker the metal wire and the less soft the metal used. Due to this stiffness, a fabric, warp-knitted fabric or knitting made of the yarn becomes difficult of processing, physiologically not well tolerable, uncomfortable when worn and poorly cleanable. Another disadvantage consists in that the displacement strength of the yarn, i.e. the cohesion between inner core and outer sheathe, is relatively poor. Still another disadvantage consists in that possibly relatively much metal wire, particularly steel wire, has to be used for shielding against electromagnetic radiation as a function of radiation frequency. As a result, the already relatively stiff fabric, warp-knitted fabric or knitting made of this yarn becomes even stiffer and thus physiologically even less tolerable and more uncomfortable.
Apart from the above-mentioned drawbacks, the covering yarns according to EP-A-250 260 and GB-A-2 018 323 have the disadvantage that they have to be produced in a two-step or multi-step process in order to avoid unfavorable yarn twisting resulting with only one covering layer around the inner core containing the metal wire.
In addition to the above-mentioned drawbacks, the yarn according to FR-A-2 599 762, has the further disadvantage that the displacement strength is especially poor because the metal wire provided within the core has very poor displacement strength with respect to the outer sheathe. As a result, the yarn is, among others, poorly processable.